In a linear motor type transportation system using a ground primary linear motor, for example, a linear synchronous motor system, a linear induction motor system or a D.C. linear motor system disposed on the ground, an amplitude and a frequency of current supplied to primary driving coils of the linear motor from an electric power converter such as a cyclo-converter and inverter arranged on the ground are controlled to carry out train traction control. In this case, one power converter unit or power substation is usually allocated to one corresponding group of trains to be driven because the frequency of the supplied current to the primary driving coils has to be controlled in response to the speed of the train. Therefore, plural power converters are needed to drive a plurality of groups of .the trains. The above power feeding system is described in the transaction papers of the 19th Japan symposium for introducing cybernetics techniques into railroad control, entitled "805 evaluation of feeding system for a magnetic floating type railroad system using a traffic simulation", September 1982, pp. 676 to 680.
Each substation supplies the corresponding feeding section with the electric power through a feeder extending along a railroad track between the stations. The power feeding line is divided into a plurality of feeding blocks and each of plural power converters is allocated to each corresponding feeding block. A rear side feeding block positioned behind a block where a train exists is designated as a keeping-off feeding section and the following train is prohibited from entering the section. In case of a system having four feeding blocks and four corresponding power converters, at the most only two groups of trains can be operated and the operation density of the train is limited.
If a feeding section being composed of a plurality of feeding blocks are allocated to each corresponding power converter and each block switch is connected between neighboring two blocks, it is possible to change the length of the feeding section by controlling on-off statuses of block switches without fixing the feeding section boundary between neighboring substations. In the above case, a rear side feeding block behind a block where a group of trains exists is designated as a keeping-off section, too. In this case, however, at the most four groups of trains are operable at the same time.
The system with a changeable boundary of the feeding section is able to increase the train operation density partially and is effective as described in the above papers when the train is delayed at a state of emergency in speed limit.
Further, in a power supply system of a traditional railroad system in which one substation is allocated to one corresponding feeding section and a plurality of trains are able to be operate within one feeding section, substation linkage system in which the feeding system for the trains is automatically changed on the basis of the comparison result between the feeding ability of a central substation and neighboring ,two substations are known as shown in Hitachi hyouron, Vol. 63, No. 11, pp. 39 to 44 (November 1981) entitled "Neighboring Interlocking control system for Tohoku-Jouetsu Shinkansen". The first traditional system fails to disclose the way in determining the feeding section of neighboring power converter unit to operate the train with safety and high density operation during the heavy traffic operation to intermittent operation of the train and power supply ability decrease of power converter fault.
On the other hand, the second traditional system is directed to the ordinary railroad system different from the linear motor type and it is not applicable to the linear motor type transportation system.